Photographic emulsions containing sensitizing dyes



Patented July 1, 1947 PHOTOGRAPHIC EMULSIONS CONTAINING SENSITIZIN G DYES Alfred W. Anish, Johnson City, and Lee C. Hensley, Binghamton, N. Y., assignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Original application August 16, 1944, Serial No. 549,788. Divided and this application August 16, 1944, Serial No. 549,790

4 Claims.

The present invention relates to the sensitizing of photographic emulsions with new compounds of the thio and seleno-carbocyanine type.

In certain processes of subtractive multi-color photography a multi-layer photographic material is used in which the lowest light-sensitive layer is sensitive only for red above 6000 A. U. This red-sensitive layer must always be insensitive to blue-green light since the presence of blue-green sensitivity gives rise to falsication of color. In al1 color-photography processes in which the color of the component picture is produced by color development, there may be present in the photographic layer in addition to the sensitizer a color former which, when the exposed silver halide emulsion is developed, combines with the oxidation product of the developer to form a sparingly soluble dye distributed in the layer proportionately to the quantity of silver image. In this case, a sensitizer must be selected, the eiect of which is not enfeeblcd by the presence of the dye component, Sensitizers are already known which have a high intensity in the red region of the spectrum but, these for the most part are enfeebled by the presence of a dye component.

It is known that many carbocyanines, of whichV the 5,6-position of the benzene nucleus is occupied, sensitize photographicsilver halide emulsions to high red sensitivity. Most of these carbocyanines, however, are not suitable for sensitizing silver halide emulsions containing color coupling components. This is thought to be due to a physical displacement which the sensitizing dye undergoes when color coupling components are added. That is, the sensitizer is adsorbed to the surface of the silver halide grain, and then, with addition of color component, is displaced therefrom.

An object of the present invention is to provide a class of sensitizers which are free from the disadvantages noted above.

A further object is to provide a new class of thio and seleno-carbocyanines which are added to photographic emulsions, or coated thereon as an over-coating, whereby the sensitivity of the photographic emulsion is increased.

4A still further object is to provide sensitizing dyes which are unaiected by the color forming development components.

Other objects and advantages of this invention will become apparent by reference to the following specification in which its preferred details and embodiments are described.

This invention is based on the discovery that thio and Selene-carbocyanines containing a cyclic hydrocarbon substituted dioxy ring struc-V ture as part of the cyanine dye molecule not only sensitize a photographic silver halide emulsion to high red sensitivity, but'are also compatible with color coupling components for the cyan dye image. In the latter combination the sensitizing action oi the dyes is not impaired or diminished. In addition to these desirable characteristics, it has been further found that when used in conjunction with color coupling components for the blue-green image, the spectral curves of these dyes show a desirable gap in the green region of the spectrum-that is, the dye sensitivity is more selective to the red spectral region. The sensitizing capacity of these dyes is not only maintained inthe presence of color formers for the blue-green image, especially those color formers containing long chain hydroxyalkyl groups, but is increased, and inrpart rendered more selective. This entirely new property is most surprising and wholly unexpected. An ad'- ditional advantage of these dyes is then ability to remain xed in the one layer in which they are voriginally deposited. 25

The sensitizing dyes suitable for the purpose of theA present invention have the general formula:

wherein R represents the methylene groups nec-l essary to complete at least a 5-membered alicyclic system such as cyclopentylidene, cyclohexylidene, cycloheptylidene and the like, R1 and Ri are alkyl groups, e. g., methyl, ethyl, propyl,

butyl, pentyl, etc., Y represents sulfur or seleni- These sensitizing dyes are obtained by condensing quaternary ammonium salts of thiazoles and selenazoles containing an alicyclie. dioxy ring such as cyclopentylidenedioxy, cyclohexyl-` idenedioxy, or cycloheptylidenedioxy ring as part of the nucleus with ethyl-orthoformate or With 2-(-acetanilido vinyl)5,6methylenedi oxybenztmazele ethiodi'de, 2(acetaniiido vinyl)-cyclohexylidenedioxybenzthiazole ethiodide, or the corresponding seleno derivatives thereof.

The alicyclicdioxybenzenes. used. in preparing the allcyclicdioxybenzthiazoles and alicyclicdi- Oxy-benzselenazoles which are condensed with any one of the above listed? intermediates or' coupling agents, are readily prepared by' reacting catechol with a. cyclic ketone as described inA Recueil Travaux Chimiques des Pays Bas, vol'. 5.4, p. 997 (1935).

The following examples describe inl the methods for accomplishing the above objects, but it is to be understood that they are inserted merely for the purpose of illustration, and are not to be construed as limiting the scope of the invention;

according` to the` above publication by dissolving 55 gms. ofcatecholin 1D0 gms.v of hot anhydrous Nine gms. of the disulfide were added to a mixture consisting of 28 cc. of acetic anhydride, 22 cc. of glacial acetic acid and 3 cc. of acetyl chloride, and heated on asteambath. Eleven gms. of zinc dust were then added in0 small portions with stirring to the heated mixture. The tree base was precipitated from the acid reaction mixture by pouring into 6 volumes of cold Water. The 2-methyl5,6cyclohexylidenedioxybenzthi azol'e was ltered, dried and had a melting point of 14d-14:2 C. The ethyl-p-toluenesulfonate salt was.` made in. the usual manner and had a meltingI point of 169 C.

0:69 gm, of the Quaternary salt thus prepared was treatedwith. 0.5 ce. of ethyl-orthoformate in 5. gms; ot. pyridine in the presence of a trace of trietliylarninev at. 13G-140 C. for 3 hours. Upon cooling, 20 cc. of Water was added. After standing' overnight, the solid that separated was disw solved in 15 cc. of hot n-propyl alcohol and the solutionv treated with 3. cc, of' 20% potassium iodide solution., filtered and allowed' to cool. The dye precipitated on standing. It was filtered oft, and: after washing with Water, the dye was recry'stallized from ethyl alcohol as the iodide. The. crystals melted above 25`0'` C.

Incorporated.` in a gelatino silver halideemulsion containing about iL-5% of silver halide, the dye sensitizedtofabout 6800 A., with a maximum sensitivity of 6400 Twenty milligrams of the sensitizing dye prepared: as above were dissolved in cc. of methyl alcohol, and' added to a kilo of silver halide gelatin emulsion containing about` 10% gelatin, 4-5% of silverhalide and 12.0'gms. of N-octadecyl-l-hydroxy-Zl-naphthoylamine. The coated emulsionhad a maximum red sensitivity at about 6650 A., and' developed to ablue-green image with p-phenylenediamine developer. The sensitizing dyedid not diffuse in multi-layer coatings.

Example II 3,3#diethyhgieyclohexylidenedioxy-5-,6-methylenedioxy-benzthiocmrbocyanne iodidecyclo'hexanone and treated' with an excess of phosphoric anhydride gms.) After the addition was completed, the stirring was continued for a', short time. andf the upper layer deca'nted. The decanted material was mixed.' with. 15u ce. of a dilutesolution of' sodium carbon-ate, and steamdistilled; The distillate was extracted with ether and the dried solvent evaporated?. The residue of the cyelohexylidenedioxybenzene Was distiiled at reduced pressure air-idftheresultlng distillate' had' a boilingpointof 125 C. at 12mm. M. Pi MQC.

The cyelohexylidenedioxybenzene was com verted to 1'12di'nitro4, 5#cyclohexylldenedioxw benzene by treating the former with a mixtureof' glacial acetic andfuming' nitric acids. The' resulting productV was then converted to the di"- Suid'e by treating it in 200- ce. of boiling ethylA alcohoi a. fused mixture of* equivalent quan-v tities of sodium suliid'e nonahydrate and sulfur in smaii portidns until a. violetA ceierl persisted for a few minutes. The solid was l-tered from the cool` mixture, washed alternately with water and alcohol'. andA dried.

methylenedioxybenzthiazole ethiodide prepared by heating at m C'. a mixture of equal Weight portions of 2-meth-yl5',6-methylenedioxybenzthiazole ethiodide and: diphen-yl'- formamdine in acetic anhydride for 40'minutes, Were mixed with an equal amount of 2methyl-5,6cyclohexyl idenedioxybenzthiazoleethyl-p-toluenesulfonate prepared according to Example I, in 5 cc. of pyridine and 3 drops of triethylam-ine. The mixture was' heated to reflux for 1 hour, cooled, and an equal volume of' Waterv added. The dye crystals which separated out on standing were ilteredl oif and recrystallized' from ethyl alcohol.

Incorporatedv in a gelatine silver halide emul-V sion containing about 4-5% of sil-'ver halide; the dye sensitized to about 6850 with a maximum sensitivity at 6420 A.

Twenty-five milligrams of the sensitizing dye above prepared weredissolved in 50 cc. of methyl alcohol, andI add'ed toa kilo of silver'halide gela tin emulsion containing about 10% gelatin, it-5%- of silver halide, and 12 gms. of 3',5'di(phenyl amino) phenol. rIfhe coated" emulsion showed- 'a- 6 high red sensitivity, and developed to a blue-green veloped to Aa blue-green image with a '1d-phenylimage with a 'p-'phenylenediamine developer. enediamine`r developer.

Example III 3.3'diethyl5,6-cyclohexylidenedioxy-5',G'-znoeflylenedioxwbenzthiobenzselenocarbocyanine o\ s /s /o\' CH2-H20 HaO/ C/ \o-cH='oH-cno on,

hexylidenedioxybenzthiazole ethiodide and 0.6 h 1 i h Vd d. 5,43 b thi i gm. of 2-methyl5,B-methylenedioxybenzselenad met y EMyc exyl eneii'e nw en' .om www, azole ethyl-p-toluenesulphonate were mixed with 25 cc. of pyridine and 0.5 cc. of triethylamine The dye solution Was diluted with Water and Hao allowed to stand overnight. The dye crystals \CH2 OHZ/ \0 y N N which separated were ltered off and Washed with Water, and recrystallized from ethyl alcohol. Y

Incorporated in a gelatine silver halide emul- 5 4 gmf of 2 9etani1id0 viny1)5,6-cyclo sion containing about 4-5% of silver halide, the hexynenedioxybenztmazole ethiodde were dyesensitized to about 6850 A., with a Amaximum mixed with 4 0 gms of 2 methy1 6 7 benzobenzo sensitivity at 6450 thiazole ethyl-'p-toluenesulfonate, 20.0 cc. pyrif TWentY'Ve milligrams 0f the sensmzmg dye dine and 4.0 cc. triethylamine. The mixture was prepared as above were added to a kilo of silver heated to reflux for one homc001ed and an equal halide gelatin emulsion containing about 10% volume of water added The dye crystals'which added. The mixture was reuxed for 1%/2 hours. 20 /CHfCH /0\ /s z/S o o-cH-=oH-oH=o gelatine-5 of silver halide and 12.0 gms. 0f N- separated out on standing were ltered off and octadecyl-l-hydroxy 2 naphthoylamine. The crystallized from methyl alcohol, coated emulsion showed a high red sensitivity, Incorporated in a gelatina silver halide emuland developed to a blue-green image' with a sion containing 45% oi' silver halide, the dye p-phenylenediamine developer. The dye did not sensitized to Aabout 6800 A., with a maximum sendiiuse in multi-layer coatings. sitivity at 6400 A.

When 8.0 gms. of l-hydroxy 2,4-dich1oronaph- Twenty-five milligrams of the sensitizing dye thalene were substituted for 12.0 gms of N-octaprepared as above were added to a kilo oi silver decyl-1-hydroxy-Z-naphthoylamine, the coated halide gelatin emulsion. containing about 10% emulsion showed a high red sensitivity, and degelatin, 4-5% of silver halide, and 10 gms. of

veloped to a blue-green image with a p-phenylo-hydroxydiphenyl as the color former. The

ene diamine developer. coated emulsion showed a high red sensitivity,

Example IV 5.3 gms. of 2-methyl-5,G-cyclopentylidenedioxyand developed to a blue-green image with a'pbenzthiazole ethyl-ptoluenesulfonate, prepared phenylenediamine developer. in a manner similar to the corresponding 2- methyl-5,6-cyclohexylidenedioxybenzthiazole in Eample VI Example I, and lve gms. of ethyl-orthoformate 3*, di th 1 1 h d di 5, dth be thi were refluxed in 20.0 cc. of pyridine for 21/2 '3 e y Moyen ggbocigdie Ime Oxy um o hours. An equal volume oi' water was added and H C H C 0 S S the dye which separated was ltered oil, washed s I \C 00H.

with water, and crystallized from methyl alcohol. 55 HC /C\ 43320114213: 00H,

Incorporated in a gelatine silver halide emul- CH2-CH: o N N sion containing 45%v of silver halide, the dye C21/i5 I (Ihm sensitized to about 6800 A., with a maximum sensitivity at 6400 A. 5.4 gms. of '2-(p-acetanilidc vinyl) 5,6cyc1o Twenty-five miligrams of the sensitzing dye hexylidenedioxybenzthiazole ethiodlde was mixed prepared as above were added to a kilo of silver with 4.2 gms. of 2-methyl-5,6-dimethoxybenzhalide gelatin emulsion containing about 10% thiazole ethyl-p-toluenesulfonate, 20 cc. of pyrigelatin, 4-5% of silver halide, and 10 gms. oi 8- dine and 4 cc. of triethylamine. The mixture was hydroxyquinoline as the color former. The coated heated to reflux for one hour, cooled, and an equal emulsion showed a high red sensitivity, and deamount of water added. The dye crystals which 7 separatedoutfon standing were vfiltered o ff crystallized from methyl alcohol. 1

Incorporated in a gelatine silver halide emulsion containing about 4-5% of silver halide, the dye sensitized to about 6800 A., with a maximum sensitivity at 6400 A.

Twenty-iive miligrams of the sensitizing dye prepared as above were added to a kilo of silver halide gelatin emulsion containing about 10% gelatin, 4-5% of silver halide, and 12 gms. of a-hydroxy naphthoic acid as the color former. The coated emulsion showed a high red sensitivity, and developed to a, blue-green image with a, p-phenylenediamine developer.

The diagrammatic spectograms constituting the accompanying drawing illustrate the regions of the spectrum to which the various types of thioand seleno-carbocyanines containing a cyclic hydrocarbon substituted dioxy ring structure as part of thecyanine dye molecule disposed herein will sensitize a-gelatino silver-halide emulsion containing about 4-5% of vsilver halide and the extent of the sensitization at Various wave lengths. The six figures of this drawing illustrate the sensitizing properties of the dyes prepared in accordance with the preceding examples. J Y

In the preparation of silver halide emulsions containing the sensitizing dyes of the present invention. the dyes maybe dissolved in methyl or ethyl alcohol and a volume solution containing from l5 .to :50 milligrams of the dye added ,to a liter of emulsion. While in general ,practiceit may not be necessary to Vadd the dye 'in larger amounts, generally, for satisfactory results, amounts usually ranging from 5 to `-2l5 vmilligrams are sufficient to obtain the maximum vsensitizing effect. However, we do not wish to limit .our invention to the quantities lust indicated; the most suitable amount will in 'each case be `found by a `few co,Imperative experiments. v'The dyes maybe added tothe emulsion in form of solutions. ln lactual practice, the dyes are applied to the emulsion during any vstage sof .its ,production; however, they are preferably added to the finished emulsion before being cast.

This application is a division of our (zo-pending application Serial No. 549,788 led on even date.

The above examples are illustrative only, and

andreshould not be construed as limiting the invention,l

since it will be apparent to those skilled in the art, that the sensitizers may be incorporated into photographic emulsions by methods other than those described herein.

While :there 'have been pointed lout .above oertain preferred embodiments of .the invention, lthe same is not limited to the foregoing examples, illustrations, or to the specific details given therein, but is capable of variations and modifications as to the reactants, proportions and conditions employed. Accordingly, it is intended'that the invention be dened only by the accompanying claims.

We claim:

l. A photographic gelatino-silver-halide emulsion which contains 3,3-diethyl5,6,5',6dicyclohexylidenedioxybenzthiocarbocyanine iodide.

2. A photographic gelatino-silver-halide emulsion which contains 3,3diethyl5,65,6-dicyolopentylidenedioxybenzthiocarbocyanine iodide.

3. A photographic gelatine-silver-halide emulsion which contains 3,3-diethyl-5,6cyclohexyli denedioxy-4',5 methylenedioxybenzselenothiazolocarbocyanine iodide.

4, A photographic `gelatino-silver-halide emu1- sion which contains a sensitizing dye of the general formula:

wherein R represents the methylene groups necessary to complete at least a 'membered valicyclic system, R1 and Re representan alkyl group, X represents an acid radical, Y represents a member taken from the class consistingof sulfur and selenium, and Z lrepresents the atoms necessary to complete a nitrogenous heterocyclic ring system.

LEE C. HENSLEY.

REFERENCES CITED The :following references :are =of lrecord in the ie of this patent:

Certificate of Correction Patent No. 2,423,217. July 1, 1947.

ALFRED W. ANISH ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 6, Example III, in the formula, extreme right hand portion thereof, for S read Se; line 32, for 4-5 read 4-5%; column 7, line 7, for "miligrams reed milligrams; and that the said Letters Patent should be reed with these corrections therein that the same may conform to the record of the oase in the Patent OHiee.

Signed and sealed this 21st day of October, A. D. 1947.

THOMAS F. MURPHY,

Assistant ommm'oner of Patents. 

